Reduce duplicated options amongst the different `pesummary` executables -- part 1

The purpose of this MR is to a) introduce a pesummary.{core/gw}.cli.parser.ArgumentParser class that inherits from the argparse.ArgumentParser class and b) move all default command line arguments to the pesummary.{core/gw}.cli.parser.ArgumentParser class. This MR reduced some of the duplicated options amongst the different pesummary executables and is therefore linked to #288.